The invention relates to a friction clutch in the drive line of a motor vehicle between internal combustion engine and gear, and especially a friction clutch consisting of a fly-wheel in rotational connection with the crank-shaft and rotatable about an axis of rotation, having a friction face, a clutch cover secured on the fly-wheel, a presser plate arranged in the clutch cover with a friction face facing the friction face of the fly-wheel and secured non-rotatably but axially displaceably on the clutch cover, a clutch main spring which initially stresses the presser plate in the direction towards the fly-wheel, a clutch disc with friction linings which is clampable in between the two friction faces and comprises a hub with internal splining for setting non-rotatably upon the external toothing of a gear shaft and release elements for the axial displacement of the presser plate against the force of the clutch main spring.
Friction clutches of the above-stated construction type are known in manifold forms. Reference may be made by way of example to German Utility Model No. 7,127,710 and to German Patent Applications 3,343,505 and 3,412,961. In these known friction clutches the clutch discs are guided and centered on the gear shaft by means of their internal splining, while the gear shaft for its part carries on its end protruding from the gear a cylindrical journal which is guided in a pilot bearing. The pilot bearing can be arranged either in a bore of the crank-shaft or in a bore of the fly-wheel.
In these known designs the expense in the fitting of gear and internal combustion engine is disadvantageous, where the clutch disc must be pre-centered during clutch assembly by means of an externally toothed mandrel guided in the pilot bearing, and the mandrel has to be removed later. The centering by means of the mandrel is affected by a radial play which subsequently renders assembly difficult, since the gear input shaft must be introduced both into the pilot bearing and into the splining of the clutch disc, in fact more or less blindly.
The present invention shows a way to simplify the assembly of the clutch, internal combustion engine and gearing and to achieve a better guidance of the clutch disc.